The nervous system

Question 1

What are the components of the nervous system?

Answer 1

The nervous system consists of the brain, spinal cord, nerves, sensory and motor nerves.

Question 2

What does the peripheral nervous system consist of?

Answer 2

Nerves that branch out from the brain and spinal cord.

Question 3

Give the meaning of nerves

Answer 3

Bundle of neurons

Question 4

Give the meaning of neurons

Answer 4

Nerve cells

Question 5

Give the meaning of a nerve impulse

Answer 5

Electrical signal that transmits along a neuron

Question 6

What following features do motor neurons have?

Answer 6

Dendrites: make connection with other neurons
Cell body that contains a nucleus and other organelles
Axon: carries nerve impulse from body cell

Question 7

What is myelin sheath?

Answer 7

Consists of Schwann cells and specialized cell wrapped around the axon

Question 8

What is the small gap called between the Schwann cells?

Answer 8

Nodes of Ranvier

Question 9

What does the combination of myelin sheath and Nodes of Ranvier increase?

Answer 9

The rate at which the nerve impulse travels along the axon

Question 10

When the axon branches, what does it form?

Answer 10

Axon endings or terminals that makes connections with motor or sensory neurons

Question 11

Sensory neurons carry —– ——– from receptors that act’s as a —- ——- towards the —

Answer 11

nerve impulses
body sensors
CNS

Question 12

Give the functions of nerve systems

Answer 12

Sensory neurons carry nerve impulse from receptors that acts as a body sensor towards the CNS.

CNS takes information contained in inputs from the sensory neuron and processes it

Sends nerve impulses via motor neurons to effector organs.

Question 13

What are nerve impulses?

Answer 13

Electrical signals transmitted from the cell body towards the axon terminals

Question 14

What happens when a neuron is at rest?

Answer 14

There is a small potential difference across the plasma membrane of around -60MV

Question 15

Phase two of synaptic transmission

Answer 15

The inside of the neuron becomes slightly more negative than the outside due to positive Na+ ions which have been pumped out of the neuron

Question 16

Phase three of synaptic transmission

Answer 16

Polarization of the plasma membrane is described as resting potential.

Question 17

Phase four of synaptic transmission

Answer 17

Nerve impulses involves a rapid change in the membrane potential, the membrane becomes depolarized so the inside is slightly more positive compared to the outside.

Question 18

Phase five of synaptic transmission

Answer 18

Process is rapidly reversed in a few milliseconds and becomes repolarized known as action potential

Question 19

Phase six of synaptic transmission

Answer 19

AP is propagated or transmitted along the axon and represents a nerve impulse

Question 20

Phase seven of synaptic transmission

Answer 20

Motor neurons are known as myelinated because they have myelin sheath, therefore AP jumps from one Node of Ranvier to the next.

Question 21

What are the connections between neurons called?

Answer 21

Synapses

Question 22

Why is transmission of a nerve impulse across a synapse not possible?

Answer 22

Because there is a gap.

Question 23

What is the nerve impulse carried across the synapse by?

Answer 23

Neurotransmitters

Question 24

Give the meaning of polarisatiom

Answer 24

Different electrical charges on either side of the plasma membrane caused by active transport of ions.

Question 25

Give the meaning of depolarisation

Answer 25

Reversal of charge difference

Question 26

Give the meaning of repolarisation

Answer 26

Restoration of orginal charge difference

Question 27

Role of synaptic knobs

Answer 27

Makes connection with muscles or another neuron.

Question 28

When a nerve impulse arrives at a synaptic knob, what occurs after?

Answer 28

It releases neurotransmitters from the membrane-based vesicles

Question 29

Give the most common neurotransmitter

Answer 29

Acetylcholine

Question 30

What is a reflex action?

Answer 30

Automatic response to an external stimulus

Question 31

Why is a reflex action important?

Answer 31

It helps to minimize injuries and it is thought of as a survival response.

Question 32

What happens when a stimulus e.g. heat is detected?

Answer 32

It is detected by the receptors in the skin and branches off the end of the sensory neuron which transmits a nerve impulse to spinal cord. Sensory neuron then makes a synapse with a relay neuron which makes a synapse with a motor neuron. The motor neuron then conducts nerve impulses to arm muscle causing it to contract.

Question 33

What is Parkinson's disease?

Answer 33

A disease that causes a loss of neurons in the substania nigra and the neurons that are lost release dopamine. Neurodegenerative disease.

Question 34

What does dopamine do?

Answer 34

It is involved in regulating movement in the body and the loss of dopamine makes it responsible for symptoms.

Question 35

How can Parkinson's directly impact the body physically?

Answer 35

- Involuntary shaking of the body creating a tremor - Slow movement - Stiff and inflexible muscles

Question 36

Give some psychological symptoms of Parkinson's

Answer 36

Anxiety and depression Balance problems Insomnia Anosmia (loss of smell) Memory problems

Question 37

Give some treatments for Parkinson's

Answer 37

Physiotherapy OT Levodopa medication Surgery

Question 38

Physiotherapy treatment

Answer 38

Improves balance and posture Strengthens muscles Increase flexibility

Question 39

Occupational Therapy

Answer 39

Makes difficult tasks easier Equipment or gadgets for practical changes

Question 40

Levodopa medication

Answer 40

Helps replace lost dopamine Can cause dramatic improvement at first but then can decrease over time.

Question 41

Give some side effects of Levodopa

Answer 41

Tiredness, sickness and dizziness

Question 42

Give some long-term side effects of dyskinesia

Answer 42

Uncontrollable jerk movements

Question 43

Surgery

Answer 43

Deep brain stimulation which involves inserting a fine wire into the brain and inserting a permanent electrode and attaching it to a pulse generator.

Question 44

What does deep brain stimulation do?

Answer 44

It delivers high electrical impulses to improve symptoms

Question 45

Give a risk of having surgery

Answer 45

Stroke